WASHINGTON (CNN) --Of 579 female Air Force Academy cadets surveyed by the Department of Defense, 43 -- or 7.4 percent -- reported they were victims of rape or attempted rape, according to a draft report of the survey results.

In all, 109 cadets indicated they had been victims of some type of sexual assault in their time at the academy. Of those, 31 respondents were seniors, 15 of whom reported they were victims of rape or attempted rape.

A Pentagon official Thursday confirmed the authenticity of the document.

The survey was conducted in May to determine the extent of sexual assault at the scandal-plagued academy, and whether commanders are doing enough to stop the assaults.

The definition of sexual assault used in the survey includes "the touching of another without their consent in a sexual manner, including attempts, in order to arouse, appeal to or gratify the lust or sexual desires of the accused, the victim or both."

More than half the women surveyed, 53.5 percent, said they believe the previous leadership of the academy failed to properly handle the sexual assault problem, while 96 percent said they believe the current leadership was making an "honest and reasonable effort to prevent or stop unwanted sexual attention," the draft report says.

The report also found many of the 109 female cadets who said they were victims of assault did not report the alleged crimes. Among the reasons cited:

• Fear of reprisal from upperclassmen not in the chain of command: 39 women (27.3 percent)

• Fear of reprisal from upperclassmen in the chain of command: 35 women (24.5 percent)

• Fear of reprisal from command officials: 36 women (25.2 percent)

• Fear of ostracism by peers: 69 women (48.3 percent)

• Fear of being punished for other infractions: 36 women (25.2 percent)

• Fear that nothing would be done: 64 women (44.8 percent)

• Embarrassment: 82 women (57.3 percent)

Fellow cadets were identified as the principal offenders in 149 (89.9 percent) of the 177 incidents of sexual assault reported in the survey. Most of the assaults -- 114, or 64.4 percent -- occurred on the grounds of the Air Force Academy installation, and of those, 65 occurred in dorms.

An Air Force Academy working group report released in June found "no systematic acceptance of sexual assault at the academy." However, the working group, headed by the top civilian Air Force lawyer, did find "the focus on sexual assault issues had varied over time and lessened in recent years," and combined with cultural and process matters to produce a "less than optimal environment" to respond to sexual assault.

Air Force Chief of Staff Gen. John Jumper replaced the academy's top four officers in March.

On Thursday, the entire 4,000-member cadet corps was lectured by the commander of cadets, Brig. Gen. Johnny Weida, because of an underage drinking incident over the weekend.

Seven 20- and 21-year-old cadets were ticketed by police for drinking alcohol in an off-campus hotel room early Saturday with two young women, aged 16 and 18.